Exxon Mobil Corp (NYSE:XOM) shares are trading lower Friday after reports surfaced that it is nearing the completion of a $60 billion acquisition.

The move sent shares of the target company, Pioneer Natural Resources Co (NYSE:PXD), nearly 10% higher.

Exxon Mobil aims to further solidify its foothold in the U.S. oil sector, especially the lucrative Permian shale basin.

Pioneer is currently the third-largest oil producer in the Permian basin behind Chevron Corporation (NYSE:CVX) and ConocoPhillips (NYSE:COP).

Exxon’s interest in Pioneer is not a recent revelation. The company has long viewed Pioneer as a potential acquisition target, due to its presence in the Permian shale region.

Reuters reported an official agreement between the two oil giants may be announced in the coming days.

This, while not hitting the previous year’s record earnings, signifies a noticeable increase from its second quarter.

Importantly, if the acquisition materializes, it will stand as Exxon’s biggest deal since its $81-billion merger with Mobil at the turn of the century. If the deal goes through, Exxon’s oil production in the region could reach 1.3 million barrels a day.

While Exxon committed to investing $17 billion through 2027 in carbon-capture technologies, including a $4.9 billion acquisition of carbon pipeline operator Denbury, the Pioneer deal underscores its sustained emphasis on its core oil business.